In spite of being the world's most famous investor, Warren Buffett's investment conglomerate Berkshire Hathaway is barely covered by Wall Street analysts.

Goldman Sachs does not produce research or recommend whether to buy or sell Berkshire shares. The same goes for JPMorgan Chase, Morgan Stanley, Bank of America Merrill Lynch and Citigroup.

In an era of increasing specialisation on Wall Street, banks may be deterred because the $200bn (£124bn) company Buffett has built over the past half century is not easily labelled. His empire stretches from Dairy Queen, the US chain of ice-cream parlours, to Acme Brick, America's biggest producer of bricks.

It is a lack of coverage that may help explain why Buffett's plan for who will eventually succeed him at the helm of Berkshire has drawn relatively little scrutiny. It would be a surprise, though, if it is not weighing on the minds of the 40,000 Berkshire shareholders who have descended this weekend on Omaha, Nebraska for the company's annual meeting.

"CEO succession plans are top-of-mind for Berkshire Hathaway investors," says Jay Gelb, who covers the company at Barclays.

The vexed question of who will step into the 81-year old's shoes has, inevitably, grown in importance as the years have passed. And it was thrust to the front of people's minds last month by Buffett's disclosure that he is suffering from stage 1 prostate cancer.

Buffett, who begins two months of radiation treatment in July, said that the cancer is not "remotely life threatening", that it will not disrupt his daily routine and that he has no intention of retiring.

The billionaire is, though, aware of shareholders' concern over what will follow the now 47-year Buffett show. In February, his annual letter to investors revealed that he and Charlie Munger, his 88-year-old business partner, had picked Berkshire's next chief executive from inside the company and that there were two back-up candidates.

"When a transfer of responsibility is required, it will be seamless, and Berkshire's prospects will remain bright," Buffett insisted.

Buffett, whose $44bn fortune makes him the world's third-wealthiest man, according to the Forbes rich list, has also explained that his responsibilities – which include managing Berkshire's $144bn of investments in companies ranging from Coca-Cola to Tesco and choosing which companies to swallow whole – will be split up when he departs.

Todd Combs, who joined Berkshire in late 2010, and Ted Weschler, who started this year, both help pick shares for Buffett and are prime candidates to take over running the whole portfolio. Meanwhile, Howard Buffett, one of his two sons, will become chairman.

Succession planning at any corporation is potentially fraught, but the dangers are magnified at Berkshire because Buffett's skill as an investor – both in buying shares in publicly traded companies and in acquiring businesses – has made him the driving force of the company's success.

Berkshire's shares have not underperformed the S&P 500 for any five-year stretch since 1965. That success and his control of 33pc of the voting rights at Berkshire have allowed him to create an unconventional company.

Just 24 people work at its headquarters in the midwestern city of Omaha, while Buffett deliberately gives the managers who run Berkshire's vast array of businesses plenty of independence.

It is why some of those analysts who do follow Berkshire want Buffett to add more flesh to the bones of the succession plan. "I'd like to know who is going to be the chief executive," said Tom Lewandowski, an analyst at stockbroker Edward Jones. "Buffett is essentially driving the bus and can do what he wants. The communication has been inadequate and will continue to be so."

At the moment, shareholders are left to speculate about potential successors they know little about.

Buffett spread the praise fairly evenly among a handful of senior figures in his shareholder letter. Ajit Jain, the Indian-born executive who runs Berkshire's reinsurance business, was applauded for adding "a great many billions of dollars to the value of Berkshire".

Buffett also said he would like to expand the "managerial domain" of James Hambrick, who joined Berkshire last year when it paid $9bn for Lubrizol, a chemicals company he ran.

Matt Rose and Greg Abel, who head railroad company Burlington Northern Santa Fe and Berkshire's energy businesses respectively, also got mentions in the annual dispatch.

Lewandowski says it would be potentially helpful if some of these senior figures who may end up succeeding Buffett had a higher profile or spoke with analysts. That would seem unlikely given that Buffett does not hold quarterly, or even annual, conference calls with analysts. One-on-one meetings with analysts or shareholders are also shunned because Buffett says he wants any new information to reach everyone at the same time.

Although that is an admirable goal, this year's shareholder meeting in the vast CenturyLink Center in downtown Omaha offered evidence that Buffett realises shareholders may not be getting as much information as they want.

For the first time, three financial analysts were allowed to pepper Buffett and Munger – who sat together at a desk accompanied only by cans of Cherry Coke – with specific questions about Berkshire and its operations.

It is a departure from the conventional line of questioning from shareholders who typically want to pick Buffett's brains on how to invest and the outlook for the global economy.

Buffett may also have introduced the format because Berkshire's shares have not been performing as well as previously over the past 18 months.

Although Berkshire shares beat the S&P 500 index in both 2008 and 2009, they lagged in 2011. So far this year, they've climbed 6.27pc compared with an 8.86pc gain for the S&P. Some of it is because riskier shares, including those of internet companies, have been in favour as investors try to lock in hefty returns while sentiment is rosier.

With its energy, railroad and insurance businesses, Berkshire's shares are less likely to flourish against that backdrop. Buffett, for his part, tells shareholders to pay attention to the book value of the shares – a measure of the value of Berkshire's assets – which climbed 4.6pc last year.

But both Lewandowski and Meyer Shields, an analyst at stockbroker Stifel Nicolas, argue that the uncertainty over the succession is also hurting.

Shields adds that any concern among shareholders will depend on when they bought into Berkshire. The company acquired new investors in 2010 when a stock split - used to pay for the $25bn acquisition of Burlington - saw enough shares issued to propel Berkshire into the S&P 500. Its entry into the S&P forced funds that track the index to buy.

The past 12 months have also seen mis-steps by a man popularly dubbed "the Sage of Omaha". At last year's gathering in Omaha, he admitted he made a "big mistake" by not quizzing David Sokol, a former lieutenant and once seen as his most likely successor, about share purchases he made in a company he then recommended Buffett buy.

Sokol, who resigned, denied he did anything wrong. Berkshire was also forced to write down the value of debt it bought in Energy Future Holdings as natural gas prices tumbled. The recovery in the US housing market that the billionaire predicted last year remains elusive.

"When you look at the historic shareholders, they've had very little reason to complain," says Shields, who has a hold rating on the shares. And some investors believe no one has any reason to complain now.

Bill Smead, who runs Smead Capital Management in Seattle, says he is not worried about the question of succession. That is in part, he explains, because the set of businesses and investments that Buffett has accumulated are designed to generate good returns and appreciate in value for decades.

"I don't know why everyone is so heated up about the succession," says Smead, who has owned Berkshire shares since the 1990s. "It is the nature of the era that we're in that people want their success fast."

Buffett ventured into technology investing for the first time in 2011 when he bought a large slice of IBM shares for $10bn and he expects the five biggest companies that Berkshire owns, excluding its insurance operations, to make record profits this year.

He is also surely right when he forecasts that Berkshire's businesses that are dependent on the housing market, including the carpet retailer Shaw, will bounce back when the US housing market does. Indeed, a strengthening of the recovery in the world's biggest economy will feed into Berkshire's bottom line because Buffett has bet so big on the US.

"Berkshire is a microcosm of the US economy," says Shields.

However, Buffett has admitted the higher returns that characterised much of Berkshire's history are becoming harder to generate given the company's sheer size. That is a challenge his successor will also face.

This year's letter to shareholders said that those pundits writing America's economic obituary will realise that the country's "best days lie ahead". It remains to be seen whether the same is true for Berkshire.

What is clearer, is that its investors and everyone else want Buffett to be around to answer that question.

The Contenders

Ajit Jain

Highly regarded by Buffett and runs Berkshire's reinsurance business

James Hambrook

Arrived at Berkshire with its $9bn purchase last year of chemicals maker Lubrizol, which Hambrick ran.

In this year's annual letter to investors Buffett said he wants to expand Hambrick's 'managerial domain'